Does the drive still read dvds ok? Have you tried using ImgBurn instead of DVDDecrypter? It is the updated burning engine from DVDDecrypter, written by the same author. You might try a simple data burn to a single layer dvd with ImgBurn first.
Have you been decrypting with DVDDecrypter as well? It is outdated for many newer dvds, and can’t handle some of the new protection schemes that have appeared in the years since development was shut down on DVDDecrypter.
DVDFab HD Decrypter is the only free decryption/ripping program I am aware of that is still being updated. http://www.dvdfab.com/free.htm